In the past, redundancy has been incorporated in some printed circuits by double ganging integrated circuit chips one upon the other, in piggy-back fashion. Such a doubling of the integrated circuit chips did not increase the memory or circuit capacity, since the chips shared the exact pin connections, including the select lead. Such doubling was for the purpose of providing increased reliability by insuring that there was a back-up chip in the event of failure.
The present invention features a doubling of integrated circuit chips upon a printed circuit board, wherein there is a true doubling of the circuit capacity or memory capacity of the printed board.
The invention utilizes the underside of the circuit board to mount additional integrated circuits to the board in essentially the same pin-hole sequences as that of the integrated circuits disposed on the top-side of the printed circuit board. The printed circuit board is modified to provide additional select leads, so that each additional chip acts independently of its coaligned host. In effect, the invention provides double circuitry from only one printed circuit. The economics and advantages obtained by such increased capacity are self-evident.
In order to achieve underside mounting of additional integrated circuit chips in the same pin-hole sequence as the top-side chips, the underside chips require a complete 180 degree reversal of their pins. This is accomplished by bending the existing pins in a diametrically opposite direction. The select pin of the underside chip is also further modified or bent to fit the new select pin-hole connection of the modified printed circuit.